Within networks, it is the network forwarding state that carries packets from the packets' network entry points to their egress points. Hop-by-hop, the forwarding state makes the network elements forward a packet to an element that is a step closer to the destination of the packet. Clearly, computing forwarding state that is in compliance with the configured network policies is crucial for the operation of the network. That is because without the proper forwarding state, the network will not deliver packets to their destinations, nor will the forwarding be done according to the configured policies.